Crystal structure and disorder in solid ${\mathrm{C}}_{70}$

Detailed analysis of the room-temperature x-ray powder-diffraction data of pure, as-prepared, solid ${\mathrm{C}}_{70}$ is reported. ${\mathrm{C}}_{70}$ adopts a hcp structure (space group P$6_3$/mmc) with a=10.53(1) Å and c=17.24(1) Å. Quantitative agreement between the observed and calculated diffraction patterns require (a) orientational disorder among the molecules, (b) the presence of ∼5% of stacking faults, and (c) a fraction of the sample to be either microcrystalline or amorphous.